Detergent composition for hard surfaces comprising hydrophilic shear-thinning polymer at very low level

ABSTRACT

A detergent composition and/or solution for floors comprising a hydrophilic shear-thinning polymer at very low level for improved cleaning end result. The solution can be used with conventional implements known in the art, including sponges, cloths and/or sponge, string, and/or strip mops and floor cloths such as those sold at retail and speciality stores. In a most preferred embodiment, the solution is used with a cleaning pad comprising an effective amount of a superabsorbent material, said pad preferably being part of cleaning implement comprising a handle and said cleaning pad preferably being removable. The detergent composition preferably contains a limited amount of a detergent surfactant, preferably linear in structure and relatively hydrophilic, the level of solvent in the formula preferably being kept below about 5.0%, and the pH preferably being maintained above about 9. The process of using the detergent solution with cleaning implements, including those of the most preferred embodiment, cleaning pad, and the provision of a kit containing both detergent composition and cleaning pad are disclosed.

This application is a 371 of International Application No PCT/US98/20513filed Oct. 1, 1998, which claims the benefit under 35 U.S.C 119(e) ofU.S. provisional application No. 60/086,447 filed May, 22, 1998 and U.S.provisional application No. 60/061,296 filed Oct. 7, 1997.

TECHNICAL FIELD

This application relates to detergent compositions that can be used forhard surfaces, and especially for floor cleaning, including conventionalapplications and implements such as sponges, cloths, sponge mops, stringmops, strip mops and floor cloths. This application is also especiallyuseful with a “disposable” cleaning implement comprising asuperabsorbent material for removing soils from hard surfaces. Thecleaning implements preferably comprise a removable absorbent cleaningpad, preferably designed so as to provide multiple cleaning surfaces.

BACKGROUND OF THE INVENTION

The literature is replete with products capable of cleaning hardsurfaces such as ceramic tile floors, hardwood floors, counter tops andthe like. In the context of cleaning floors, numerous devices aredescribed comprising a handle and some means for absorbing a fluidcleaning composition. Such devices include those that are reusable,including mops containing cotton strings, cellulose and/or syntheticstrips, sponges, and the like. The use of any such device or moprequires considerable effort.

Examples of disposable mops include: U.S. Pat. No. 5,094,559, issuedMar. 10, 1992 to Rivera et al., which describes a mop that includes adisposable cleaning pad comprising a scrubber layer for removing soilfrom a soiled surface, a blotter layer to absorb fluid after thecleaning process, and a liquid impervious layer positioned between thescrubber and blotter layer and U.S. Pat. No. 5,419,015, issued May 30,1995 to Garcia, which describes a mop having removable, washable workpads, said patents being incorporated herein by reference.

The cleaning implement herein preferably comprises a removable cleaningpad, which alleviates the need to rinse the pad during use. Thiscleaning pad preferably possesses sufficient absorbent capacity, on agram of absorbed fluid per gram of cleaning pad basis, to allow thecleaning of a large area, such as that of the typical hard surface floor(e.g., 80–100 ft²), without the need to change the pad. This typicallyrequires the use of a superabsorbent material, preferably of the typedisclosed hereinafter. The detergent composition that is used with suchsuperabsorbent matierials must be carefully formulated to avoiddefeating the goal of using such superabsorbent material.

The preferred cleaning implements have a pad which offers beneficialsoil removal properties due to continuously providing a fresh surface,and/or edge to contact the soiled surface, e.g., by provideng aplurality of surfaces that contact the soiled surface during thecleaning operation.

SUMMARY OF THE INVENTION

Detergent compositions used for cleaning hard surfaces such as floors,either full strength, or diluted, will normally contain sufficientdetergent ingredients such as surfactant, builder, solvent etc., toenable the solution to provide excellent end result cleaning withoutcausing build-up or stickiness. End use is based on how the product isintended for use; diluted, such as in case of floor cleaners andmulti-purpose cleaners, or neat, such as in the case of sprays out of abottle or sprays out of a mopping implement that is used with disposableor re-usable pads.

Typically the “end use” cleaning solution, either full strength, ordiluted, contains less than about 0.5% by weight of the solution ofdetergent surfactant. The level of detergent surfactant in the end usecleaning solution is preferably from about 0.01% to about 0.5%, morepreferably from about 0.05% to about 0.4%, and even more preferably fromabout 0.05% to about 0.3%, by weight of the composition/cleaningsolution. To aid in cleaning, one or more cleaning solvents, preferablyhydrophobic cleaning solvents, can also be present. The level ofsolvent(s), when present, in the end use cleaning solution is preferablyfrom about 0.1% to about 5.0%, more preferably from about 0.25% to about4.0%, and even more preferably from about 0.5% to about 3.0%, by weightof the composition/cleaning solution.

To aid in cleaning when using conventional implements, e.g., cloths,sponges, and mops such as sponge, strip, or string, and to avoidhindering absorption when using with a pad containing superabsorbentmaterials, the pH is preferably more than about 9, more preferably morethan about 9.5, and even more preferably more than about 10. Thealkalinity should preferably be provided, at least in part, by volatilematerials, to avoid streaking/filming problems.

For the purpose of helping to level the solution during drying thecomposition should contain a polymer that has hydrophilic andshear-thinning characteristics that is capable of inhibiting molecularaggregation of surfactant solution on floors during the dry-down processto provide one, or more, of the benefits of: strippability; avoidance ofbuild-up; easy spreading of solution on hard surfaces such as floors;and maintaining a sufficient amount of water on the surface to level theingredients remaining on the surface. By leveling we mean minimizingsolution de-wetting from the surface during drying which, in turn,minimizes streaking. Because of this benefit, the polymer allowsformulation at even low surfactant levels and allows for addition ofsolvents to aid in cleaning without hurting filming/streaking. Overallthis can also lead to less residue and floor stickiness.

The essential polymer herein is preferably present at only a very lowlevel, that is from about 0.0001% to about 0.2%, preferably from about0.0001% to about 0.1%, more preferably from about 0.0005% to about0.08%, by weight of the cleaning solution. The level in product willreflect the type of use, full strength, or dilute. The polymer ispreferably selected from the group consisting of; natural gums,especially xanthan gums, guar gums, gum arabic, and/or pectin; syntheticpolymers such as poly(styrene sulfonate); poly(vinyl pyrrolidone); andmixtures thereof, as monomers and/or polymers. The most preferred isxanthan gum.

The detergent surfactant is preferably predominantly linear, e.g.,aromatic groups should not be present, and the detergent surfactant ispreferably relatively water soluble, e.g., having a hydrophobic chaincontaining from about 8 to about 14, preferably from about 8 to about12, carbon atoms, and, for nonionic detergent surfactants, having an HLBof from about 9 to about 14, preferably from about 10 to about 13, morepreferably from about 10 to about 12.

The composition can be used in the context of conventional hard surface,e.g., floor or multi-purpose cleaners and with conventional cleaningand/or mopping systems known in the art such as sponges and cloths,e.g., sponge mops, strip mops, string mops and floor cloths.Additionally, a preferred aspect the present invention relates to theuse of the cleaning solutions/compositions with an all-in-one implementplus cleaning pad system. The cleaning pad preferably contains asuberabsorbent material and works synergistically with the describeddetergent composition/solution to provide better end result cleaningwith greater convenience. This cleaning system is typically comprisedof:

-   -   a. a handle; and    -   b. a removable cleaning pad comprising a suberabsorbent material        and having a plurality of substantially planar surfaces, wherein        each of the substantially planar surfaces contacts the surface        being cleaned, and preferably a pad structure which has both a        first layer and a second layer, wherein the first layer is        located between the scrubbing layer and the second layer and has        a smaller width than the second layer.

Depending on the means used for attaching the cleaning pad to thecleaning implement's handle, it may be preferable for the cleaning padto further comprise a distinct attachment layer. In these embodiments,the absorbent layer would be positioned between the scrubbing layer andthe attachment layer.

The detergent composition and, preferably, the implement of the presentinvention are compatible with all hard surface substrates, includingwood, vinyl, linoleum, no wax floors, ceramic, Formica®, porcelain,glass, wall board, and the like. The implement and detergent compositionprovide ease of cleaning, especially when the polymer is present toprovide easier mopping and better results.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a cleaning implement used in thepreferred embodiment which has an on-board fluid dispensing device whichwill dispense the detergent composition.

FIG. 1 a is a perspective view of a cleaning implement used in thepreferred embodiment which does not have an on-board fluid dispensingdevice, so that the composition is supplied separately.

FIG. 1 b is a side view of the handle grip of the implement shown inFIG. 1 a.

FIG. 2 is a perspective view of a removable cleaning pad of theimplement.

FIG. 3 is a perspective view of an absorbent layer of a disposablecleaning pad used in the preferred embodiment.

FIG. 4 is a blown perspective view of the absorbent layer of a removablecleaning pad used in the preferred embodiment.

FIG. 5 is a cross sectional view of a cleaning pad used in the preferredembodiment, taken along the y-z plane.

DETAILED DESCRIPTION

I. Detergent Composition

The detergent composition acts as a cleaning solution either when usedfull strength, or when diluted. The level of ingredients, therefore,have to be considered in the context of the end use. The essentialpolymer is only used at very low levels in the cleaning solution.Therefore, any concentrated composition should be packaged inassociation with instructions to dilute to the proper level.

The Polymer

As discussed hereinbefore, the level of polymer should be low, e.g.,that is from about 0.0001% to about 0.2%, preferably from about 0.0001%to about 0.1% more preferably from about 0.0005% to about 0.08%, byweight of the composition. This very low level is all that is requiredto produce a better end result cleaning and higher levels can causestreaking/filming, build up, and/or stickiness.

While not wishing to be limited by theory, two physical properties areconsidered critical for the polymer: 1) Hydrophilic nature and 2)Shear-thinning ability. The polymer hydrophilicity is important toensure strippability in-between cleanings to avoid build-up. Theshear-thinning characteristic is important in aiding to spread solutionout evenly during use and combined with hydrophilic characterstic helpsprovide leveling effect. By leveling effect we mean minimizing solutionde-wetting and molecular aggregation which typically occurs during drydown. Molecular aggregation leads to visual streaking/filming which is asignal of poor end result cleaning.

Suitable examples of polymers include cellulose materials, e.g.,carboxy-methylcellulose, hydroxymethylcellulose, etc., and synthetichydrophilic polymers such as polystyrene sulfonate. More preferred arenaturally occurring polymers like gum arabic, pectin, guar gum andxanthan gum. Xanthan gum is pariticularly preferred. Xanthan gum isdisclosed in U.S. Pat. No. 4,788,006, Bolich, issued Nov. 29, 1986, atCol. 5, line 55 through Col. 6, line 2, said patent being incorporatedherein by reference. Many synthetic polymers can provide this benefit,especially polymers that contain hydrophilic groups, e.g., carboxylategroups. Other polymers that can provide shear-thinning andhydrophilicity include cationic materials that also contain hydrophilicgroups and polymers that contain multiple ether linkages. Cationicmaterials include cationic sugar and/or starch derivatives.

Preferred polymers are those having higher molecular weights, althoughmolecular weights down to about 5,000 can provide some results. Ingeneral, the polymers should have molecular weights of more than about10,000, preferably more than about 100,000, more preferably more thanabout 250,000, and even more preferably more than about 500,000. Themolecular weight should normally be, from about 10,000 to about 100,000;preferably from about 100,000 to about 1,000,000; more preferably fromabout 1,000,000 to about 4,000,000; and even more preferably greaterthan 4,000,000 million.

Examples of suitable materials for use herein include polymerspreferably selected from the group consisting of xanthan gums, guargums, gum arabic, pectin poly(styrene sulfonate), and mixtures thereofof monomers and/or polymers. These polymers can also be used incombination with polymers that do not provide the benefit or provide thebenefit to lesser extent to achieve an improved end result cleaning. Themost preferred is xanthan gum.

The polymer used is preferably one that provides shear-thinning,especially for ease of dispensing. Compositions which are inherentlyshear-thinning can be used full strength without modification. Hardsurface detergent compositions and especially the preferred detergentcompositions described herein should have a viscosity of less than about250 cps, preferably less than about 100 cps, and even more preferablyless than about 15. The viscosity is determined using a BrookfieldSynchroelectric Viscometer, model LVT, made by Brookfield EngineeringLaboratory, Inc., Stoughton, Mass., using a No. 1 spindle at 60 rpm, andat a temperature of about 20° C. (Constant shear rate of about 13inverse seconds.)

Shear-thinning characteristics of, e.g., polymers and/or compositions,are determined using a Carrimed Controlled Stress Rheometer Model CSL100, made by Carrimed Ltd., Interpret House, Curtis Road Estate,Dorking, Surry RH 4 1DP, England. The Rheometer employs doubleconcentric cylinders geometry to make steady shear measurements atvarious shear rates. These measurements are made at about 26° C. Theshear-thinning, pseudoplastic behavior of the xanthan gum system can bemathematically modeled by the equation:N=KR ^(n−1)where N is the apparent viscosity, K is the consistency constant, R isthe shear rate, and n is the shear index. For best spraying results(dispensing) the values of K and n should give viscosities below 15 cpsat spraying shear rates (˜10,000 inversed seconds, as reported in tradeliterature).

Shear-thinning behavior is described in U.S. Pat. No. 4,783,283,Stoddart, issued Nov. 8, 1988, especially the portion appearing atcolumn 2, line 46, et seq.

The Detergent Surfactant

Detergent surfactants that are used in hard surface cleaner compositionsinclude anionic, nonionic, amphoteric (including zwitterionic), andcationic detergent surfactants and mixtures thereof. Suitable detergentsare well known in the art and include those described in U.S. Pat. No.4,111,854, Spadini et al., issued Sep. 5, 1978; U.S. Pat. No. 4,424,408,Imamura et al., issued Jan. 27, 1981; U.S. Pat. No. 4,414,128, Goffinet,issued Nov. 8, 1983; U.S. Pat. No. 4,612,135, Wenzel, issued Sep. 16,1986; U.S. Pat. No. 4,743,395, Leifheit, issued May 10, 1988; U.S. Pat.No. 4,749,509, Kacher, issued Jun. 7, 1988; U.S. Pat. No. 4,759,867,Choy et al., issued Jul. 26, 1988; U.S. Pat. No. 4,769,172, Siklosi,issued Sep. 6, 1988; U.S. Pat. No. 4,804,491, Choy et al., issued Feb.14, 1989; and U.S. Pat. No. 4,895,669, Choy et al., issued Jan. 23,1990, all of said patents being incorporated herein by reference.

Detergent compositions, or solutions, especially those which are to beused with an implement containing a superabsorbent material, preferred,require sufficient detergent to enable the solution to provide cleaningwithout overloading the superabsorbent material with solution, but thesolutions cannot normally have more than about 0.5% by weight of thesolution of detergent surfactant without the performance suffering.Therefore, the level of detergent surfactant in the cleaning solutionshould be from about 0.01% to about 0.5%, more preferably from about0.05% to about 0.4%, and even more preferably from about 0.05% to about0.3%, by weight of the solution/composition. The preferred solution canalso contain one or more solvents to aid cleaning at a level preferablyfrom about 0.1% to about 5.0%, more preferably from about 0.25% to about3.0%, and even more preferably from about 0.5% to about 2%, of thesolution.

As discussed before, the pH should be more than about 9.3, preferablymore than about 10, more preferably more than about 10.3, to aid incleaning when using conventional systems such as sponges, cloths, andmops such as sponge mops, strip mops, string mops mops, floor cloths,etc., and to avoid hindering absorption when using with pad containingsuperabsorbent materials, and the alkalinity should preferably beprovided, at least in part, by volatile materials, to avoidstreaking/filming problems.

The detergent surfactant is preferably linear, e.g., branching andaromatic groups should not be present, and the detergent surfactant ispreferably relatively water soluble, e.g., having a hydrophobic chaincontaining from about 8 to about 14, preferably from about 8 to about12, carbon atoms, and, for nonionic detergent surfactants, having an HLBof from about 9 to about 14, preferably from about 10 to about 13, morepreferably from about 10 to about 12.

The invention also comprises a detergent composition as disclosed hereinin a container in association with instructions to use it with animplement comprising an effective amount of a superabsorbent material,and, optionally, in a container in a kit comprising the implement, or,at least, a disposable cleaning pad comprising a superabsorbentmaterial. The invention also relates to the use of the composition and acleaning pad comprising a suberabsorbent material to effect cleaning ofsoiled surfaces.

The detergent composition, (cleaning solution) is an aqueous-basedsolution comprising one or more detergent surfactants, alkalinematerials to provide the desired alkaline pH, and optional solvents,builders, chelants, suds suppressors, enzymes, etc. Suitable surfactantsinclude anionic, nonionic, zwitterionic, and amphoteric surfactants asdiscussed above, preferably anionic and nonionic detergent surfactantshaving hydrophobic chains containing from about 8 to about 14,preferably from about 8 to about 12, carbon atoms. Examples of anionicsurfactants include, but are not limited to, linear alkyl sulfates,alkyl sulfonates, and the like. Examples of nonionic surfactants includealkylethoxylates and the like. Examples of zwitterionic surfactantsinclude betaines and sulfobetaines. Examples of amphoteric surfactantsinclude alkylampho glycinates, and alkyl imino propionate. All of theabove materials are available commercially, and are described inMcCutcheon's Vol. 1: Emulsifiers and Detergents, North American Ed.,McCutheon Division, MC Publishing Co., 1997, incorporated herein byreference.

The Solvent

Suitable solvents include short chain (e.g., C₁–C₆) derivatives ofoxyethylene glycol and oxypropylene glycol, such as mono- anddi-ethylene glycol n-hexyl ether; mono-, di- and tri-propylene glycoln-butyl ether; and the like. Other volatile solvents such as ethanol,isopropanol and the like are also preferred in the context of thepresent invention.

The Sud Suppressor

Suitable suds suppressors include silicone polymers and linear orbranched C₁₀–C₁₈ fatty acids, paraffins or alcohols. Dow Corning AF(contains: Polyethylene glycol stearate (4% Wt, CAS # 9004993);Methylated silica (2% Wt, CAS # 67762907); Octamethyl cyclotetrasiloxane(2% Wt, CAS # 556672) is preferred.

The suds suppressor at an effective level, typically from about 0.0005to about 0.02, preferably from about 0.001 to about 0.01, morepreferably from about 0.002 to about 0.003%, by weight of thesolution/composition, provides a technical improvement in spotting andfilming, particularly on ceramic surfaces. The reason for this is thegrout lines on ceramic create low spots as the mop moves across,generating suds. If too high a level of suds is generated, it can drydown into streaks. Furthermore, consumer research shows that suds seenon floor during mopping is perceived by some consumers as leading tofilm/streaking.

Lowering suds on floor during mopping can provide varying degrees oftechnical and perceptual benefits for not leaving film/streaks. Thedegree of benefit depends on the level of suds created and to whatdegree the level of suds is controlled. particularly during mopping.

Known suds suppressors can be used, but it is highly desirable to use asilicone suds suppressor since they are effective at very low levels andtherefore can minimize the total water insoluble material needed whilehaving at least an effective amount of suds suppressor present.

Builders

Suitable builders include those soluble, especially alkali metal, e.g.,sodium and/or potassium and/or amine and/or substituted amine, salts ofconventional builders, including those derived from phosphorous sources,such as orthophosphate and pyrophosphate, and non-phosphorous sources,such as nitrilotriacetic acid, S,S-ethylene diamine disuccinic acid, andthe like. Suitable chelants include ethylenediaminetetraacetic acid andcitric acid, and the like.

Optional Ingredients

Suitable enzymes include lipases, proteases, amylases and other enzymesknown to be useful for catalysis of soil degradation. The total level ofsuch ingredients is low, preferably less than about 0.1%, morepreferably less than about 0.05%, to avoid causing filming/streakingproblems. Preferably, the compositions should be essentially free ofmaterials that cause filming/streaking problems. Accordingly, it isdesirable to use alkaline materials that do not cause filming and/orstreaking for the majority of the buffering. Suitable alkaline buffersare carbonate, bicarbonate, citrate, etc. The preferred alkaline buffersare alkanol amines having the formula:CR₂(NH₂)CR₂OHwherein each R is selected from the group consisting of hydrogen andalkyl groups containing from one to four carbon atoms and the total ofcarbon atoms in the compound is from three to six, preferably,2-amino-2-methylpropanol.

A suitable cleaning solution for use with the present implementcomprises from about 0.05% to about 0.3% of detergent surfactant,preferably comprising a linear alcohol ethoxylate detergent surfactant(e.g., Neodol 1-5®, available from Shell Chemical Co.) and analkylsulfonate (e.g., Bioterge® PAS-8s, a linear C₈ sulfonate availablefrom Stepan Co.); from about 0.5 to about 2.0% propylene glycol n-butylether (Dow Co.), from about 0.5% to about 3.0% ethanol (Quantumchemicals), from about 0.05% to about 0.25%, of volatile alkalinematerial, e.g., 2-amino-2-methyl-1-propanol; optional adjuvents suchdyes and/or perfumes; and from about 99.9% to about 90% deionized orsoftened water.

II. The Implement Plus Cleaning Pad System

The implemment plus cleaning pad system in the preferred embodiment isbased on providing convenience. Therefore, it is preferable to use animplement which comprises a cleaning pad, preferably removable and/ordisposable, that contains a superabsorbent material and which preferablyalso provides significant cleaning benefits. The preferred cleaningperformance benefits are related to the preferred structuralcharacteristics described below, combined with the ability of the pad towork synergistically with the present invention to remove soils. Thecleaning pad, as described herein requires the use of the detergentcomposition, as described hereinafter, to provide optimum performance.

The cleaning pads will preferably have an absorbent capacity whenmeasured under a confining pressure of 0.09 psi after 20 minutes (1200seconds) (hereafter refered to as “t₁₂₀₀ absorbent capacity”) of atleast about 10 g deionized water per g of the cleaning pad. Theabsorbent capacity of the pad is measured at 20 minutes (1200 seconds)after exposure to deionized water, as this represents a typical time forthe consumer to clean a hard surface such as a floor. The confiningpressure represents typical pressures exerted on the pad during thecleaning process. As such, the cleaning pad should be capable ofabsorbing significant amounts of the cleaning solution within this 1200second period under 0.09 psi. The cleaning pad will preferably have at₁₂₀₀ absorbent capacity of at least about 15 g/g, more preferably atleast about 20 g/g, still more preferably at least about 25 g/g and mostpreferably at least about 30 g/g. The cleaning pad will preferably havea t₉₀₀ absorbent capacity of at least about 10 g/g, more preferably at₉₀₀ absorbent capacity of at least about 20 g/g.

Values for t₁₂₀₀ and t₉₀₀ absorbent capacity are measured by theperformance under pressure (referred to herein as “PUP”) method, whichis described in detail in the Test Methods section below.

The cleaning pads will also preferably, but not necessarily, have atotal fluid capacity (of deionized water) of at least about 100 g, morepreferably at least about 200 g, still more preferably at least about300 g and most preferably at least about 400 g. While pads having atotal fluid capacity less than 100 g are within the scope of theinvention, they are not as well suited for cleaning large areas, such asseen in a typical household, as are higher capacity pads.

Absorbent Layer

The absorbent layer serves to retain any fluid and soil absorbed by thecleaning pad during use. While the preferred scrubbing layer, describedhereinafter, has some affect on the pad's ability to absorb fluid, theabsorbent layer plays the major role in achieving the desired overallabsorbency. Furthermore, the absorbent layer preferably comprisesmultiple layers which are designed to provide the cleaning pad withmultiple planar surfaces.

From ta fluid absorbency perspective, the absorbent layer will becapable of removing fluid and soil from any “scrubbing layer” so thatthe scrubbing layer will have capacity to continually remove soil fromthe surface. The absorbent layer also should be capable of retainingabsorbed material under typical in-use pressures to avoid “squeeze-out”of absorbed soil, cleaning solution, etc.

The absorbent layer can comprise any material that is capable ofabsorbing and retaining fluid during use. To achieve desired total fluidcapacities, it is preferred to include in the absorbent layer a materialhaving a relatively high capacity (in terms of grams of fluid per gramof absorbent material). As used herein, the term “superabsorbentmaterial” means any absorbent material having a g/g capacity for waterof at least about 15 g/g, when measured under a confining pressure of0.3 psi. The cleaning solutions (compositions) disclosed above areaqueous based, so it is preferred that the superabsorbent materials havea relatively high g/g capacity for water or water-based fluids.

Representative superabsorbent materials include water insoluble,water-swellable superabsorbent gelling polymers (referred to herein as“superabsorbent gelling polymers”) which are well known in theliterature. These materials demonstrate very high absorbent capacitiesfor water. The superabsorbent gelling polymers useful in the presentinvention can have a size, shape and/or morphology varying over a widerange. These polymers can be in the form of particles that do not have alarge ratio of greatest dimension to smallest dimension (e.g., granules,flakes, pulverulents, interparticle aggregates, interparticlecrosslinked aggregates, and the like) or they can be in the form offibers, sheets, films, foams, laminates, and the like. The use ofsuperabsorbent gelling polymers in fibrous form provides the benefit ofproviding enhanced retention of the superabsorbent material, relative toparticles, during the cleaning process. While their capacity isgenerally lower for aqueous-based mixtures, these materials stilldemonstrate significant absorbent capacity for such mixtures. The patentliterature is replete with disclosures of water-swellable materials.See, for example, U.S. Pat. No. 3,699,103 (Harper et al.), issued Jun.13, 1972; U.S. Pat. No. 3,770,731 (Harmon), issued Jun. 20, 1972; U.S.Reissue Pat. No. 32,649 (Brandt et al.), reissued Apr. 19, 1989; U.S.Pat. No. 4,834,735 (Alemany et al.), issued May 30, 1989, said patentsbeing incorporated herein by reference.

Superabsorbent gelling polymers useful in the present invention includea variety of water-insoluble, but water-swellable polymers capable ofabsorbing large quantities of fluids. Such polymeric materials are alsocommonly referred to as “hydrocolloids”, and can include polysaccharidessuch as carboxymethyl starch, carboxymethyl cellulose, and hydroxypropylcellulose; nonionic types such as polyvinyl alcohol, and polyvinylethers; cationic types such as polyvinyl pyridine, polyvinylmorpholinione, and N,N-dimethylaminoethyl or N,N-diethylaminopropylacrylates and methacrylates, and the respective quaternary saltsthereof. Typically, superabsorbent gelling polymers that are useful havea multiplicity of anionic functional groups, such as sulfonic acid, andmore typically carboxy, groups. Examples of polymers suitable for useherein include those which are prepared from polymerizable, unsaturated,acid-containing monomers. Thus, such monomers include the olefinicallyunsaturated acids and anhydrides that contain at least one carbon tocarbon olefinic double bond. More specifically, these monomers can beselected from olefinically unsaturated carboxylic acids and acidanhydrides, olefinically unsaturated sulfonic acids, and mixturesthereof.

Some non-acid monomers can also be included, usually in minor amounts,in preparing the superabsorbent gelling polymers useful herein. Suchnon-acid monomers can include, for example, the water-soluble orwater-dispersible esters of the acid-containing monomers, as well asmonomers that contain no carboxylic or sulfonic acid groups at all.Optional non-acid monomers can thus include monomers containing thefollowing types of functional groups: carboxylic acid or sulfonic acidesters, hydroxyl groups, amide-groups, amino groups, nitrile groups,quaternary ammonium salt groups, aryl groups (e.g., phenyl groups, suchas those derived from styrene monomer). These non-acid monomers arewell-known materials and are described in greater detail, for example,in U.S. Pat. No. 4,076,663 (Masuda et al), issued Feb. 28, 1978, and inU.S. Pat. No. 4,062,817 (Westerman), issued Dec. 13, 1977, both of whichare incorporated by reference.

Olefinically unsaturated carboxylic acid and carboxylic acid anhydridemonomers include the acrylic acids typified by acrylic acid itself,methacrylic acid, ethacrylic acid, α-chloroacrylic acid, a-cyanoacrylicacid, β-methylacrylic acid (crotonic acid), α-phenylacrylic acid,β-acryloxypropionic acid, sorbic acid, α-chlorosorbic acid, angelicacid, cinnamic acid, p-chlorocinnamic acid, β-sterylacrylic acid,itaconic acid, citroconic acid, mesaconic acid, glutaconic acid,aconitic acid, maleic acid, fumaric acid, tricarboxyethylene and maleicacid anhydride.

Olefinically unsaturated sulfonic acid monomers include aliphatic oraromatic vinyl sulfonic acids such as vinylsulfonic acid, allyl sulfonicacid, vinyl toluene sulfonic acid and styrene sulfonic acid; acrylic andmethacrylic sulfonic acid such as sulfoethyl acrylate, sulfoethylmethacrylate, sulfopropyl acrylate, sulfopropyl methacrylate,2-hydroxy-3-methacryloxypropyl sulfonic acid and2-acrylamide-2-methylpropane sulfonic acid.

Preferred superabsorbent gelling polymers for use in the presentinvention contain carboxy groups. These polymers include hydrolyzedstarch-acrylonitrile graft copolymers, partially neutralized hydrolyzedstarch-acrylonitrile graft copolymers, starch-acrylic acid graftcopolymers, partially neutralized starch-acrylic acid graft copolymers,saponified vinyl acetate-acrylic ester copolymers, hydrolyzedacrylonitrile or acrylamide copolymers, slightly network crosslinkedpolymers of any of the foregoing copolymers, partially neutralizedpolyacrylic acid, and slightly network crosslinked polymers of partiallyneutralized polyacrylic acid. These polymers can be used either solelyor in the form of a mixture of two or more different polymers. Examplesof these polymer materials are disclosed in U.S. Pat. No. 3,661,875,U.S. Pat. No. 4,076,663, U.S. Pat. No. 4,093,776, U.S. Pat. No.4,666,983, and U.S. Pat. No. 4,734,478, all of said patents beingincorporated herein by reference.

Most preferred polymer materials for use in making the superabsorbentgelling polymers are slightly networked crosslinked polymers ofpartially neutralized polyacrylic acids and starch derivatives thereof.Most preferably, the hydrogel-forming absorbent polymers comprise fromabout 50% to about 95%, preferably about 75%, neutralized, slightlynetwork crosslinked, polyacrylic acid (i.e. poly(sodium acrylate/acrylicacid)). Network crosslinking renders the polymer substantiallywater-insoluble and, in part, determines the absorptive capacity andextractable polymer content characteristics of the superabsorbentgelling polymers. Processes for network crosslinking these polymers andtypical network crosslinking agents are described in greater detail inU.S. Pat. No. 4,076,663, incorporated herein by reference.

While the superabsorbent gelling polymers are preferably of one type(i.e., homogeneous), mixtures of polymers can also be used in theimplements used in the preferred embodiment. For example, mixtures ofstarch-acrylic acid graft copolymers and slightly network crosslinkedpolymers of partially neutralized polyacrylic acid can be used in thepresent invention.

While any of the superabsorbent gelling polymers described in the priorart can be useful in the present invention, it has recently beenrecognized that where significant levels (e.g., more than about 50% byweight of the absorbent structure) of superabsorbent gelling polymersare to be included in an absorbent structure, and in particular whereone or more regions of the absorbent layer will comprise more than about50%, by weight of the region, the problem of gel blocking by the swollenparticles may impede fluid flow and thereby adversely affect the abilityof the gelling polymers to absorb to their full capacity in the desiredperiod of time. U.S. Pat. No. 5,147,343 (Kellenberger et al.), issuedSep. 15, 1992 and U.S. Pat. No. 5,149,335 (Kellenberger et al.), issuedSep. 22, 1992, said patents being incorporated herein by reference,describe superabsorbent gelling polymers in terms of their AbsorbencyUnder Load (AUL), where gelling polymers absorb fluid (0.9% saline)under a confining pressure of 0.3 psi. (The disclosure of each of thesepatents is incorporated herein.) The methods for determing AUL aredescribed in these patents. Polymers described therein can beparticularly useful in embodiments of the present invention that containregions of relatively high levels of superabsorbent gelling polymers. Inparticular, where high concentrations of superabsorbent gelling polymerare incorporated in the cleaning pad, those polymers will preferablyhave an AUL, measured according to the methods described in U.S. Pat.No. 5,147,343, incorporated herein by reference, of at least about 24ml/g, more preferably at least about 27 ml/g after 1 hour; or an AUL,measured according to the methods described in U.S. Pat. No. 5,149,335,incorporated herein by reference, of at least about 15 ml/g, morepreferably at least about 18 ml/g after 15 minutes. Commonly assignedcopending U.S. application Ser. No. 08/219,547 (Goldman et al.), filedMar. 29, 1994 and U.S. application Ser. No. 08/416,396 (Goldman et al.),filed Apr. 6, 1995 (both of which are incorporated by reference herein),also address the problem of gel blocking and describe superabsorbentgelling polymers useful in overcoming this phenomena. These applicationsspecifically describe superabsorbent gelling polymers which avoid gelblocking at even higher confining pressures, specifically 0.7 psi. Inthe embodiments of the present invention where the absorbent layer willcontain regions comprising high levels (e.g., more than about 50% byweight of the region) of superabsorbent gelling polymer, it may bepreferred that the superabsorbent gelling polymer be as described in theaforementioned applications by Goldman et al.

Other useful superbsorbent materials include hydrophilic polymericfoams, such as those described in commonly assigned copending U.S.patent application Ser. No. 08/563,866 (DesMarais et al.), filed Nov.29, 1995 and U.S. Pat. No. 5,387,207 (Dyer et al.), issued Feb. 7, 1995,said patents being incorporated herein by reference. These referencesdescribe polymeric, hydrophilic absorbent foams that are obtained bypolymerizing a high internal phase water-in-oil emulsion (commonlyreferred to as HIPEs). These foams are readily tailored to providevarying physical properties (pore size, capillary suction, density,etc.) that affect fluid handling ability. As such, these materials areparticularly useful, either alone or in combination with other suchfoams or with fibrous structures, in providing the overall capacity.

Where superabsorbent material is included in the absorbent layer, theabsorbent layer will preferably comprise at least about 15%, by weightof the absorbent layer, more preferably at least about 20%, still morepreferably at least about 25%, of the superabsorbent material.

The absorbent layer can also consist of or comprise fibrous material.Fibers useful in the present invention include those that are naturallyoccurring (modified or unmodified), as well as synthetically madefibers. Examples of suitable unmodified/modified naturally occurringfibers include cotton, Esparto grass, bagasse, hemp, flax, silk, wool,wood pulp, chemically modified wood pulp, jute, ethyl cellulose, andcellulose acetate. Suitable synthetic fibers can be made from polyvinylchloride, polyvinyl fluoride, polytetrafluoroethylene, polyvinylidenechloride, polyacrylics such as ORLON®, polyvinyl acetate, RAYON®,polyethylvinyl acetate, non-soluble or soluble polyvinyl alcohol,polyolefins such as polyethylene (e.g., PULPEX®) and polypropylene,polyamides such as nylon, polyesters such as DACRON® or KODEL®,polyurethanes, polystyrenes, and the like. The absorbent layer cancomprise solely naturally occurring fibers, solely synthetic fibers, orany compatible combination of naturally occurring and synthetic fibers.

The fibers useful herein can be hydrophilic, hydrophobic or can be acombination of both hydrophilic and hydrophobic fibers. As indicatedabove, the particular selection of hydrophilic or hydrophobic fiberswill depend upon the other materials included in the absorbent (and tosome degree the scrubbing) layer. That is, the nature of the fibers arepreferably such that the cleaning pad exhibits the preferred fluid delayand overall fluid absorbency. Suitable hydrophilic fibers for use in thepresent invention include cellulosic fibers, modified cellulosic fibers,rayon, polyester fibers such as hydrophilic nylon (HYDROFIL®). Suitablehydrophilic fibers can also be obtained by hydrophilizing hydrophobicfibers, such as surfactant-treated or silica-treated thermoplasticfibers derived from, for example, polyolefins such as polyethylene orpolypropylene, polyacrylics, polyamides, polystyrenes, polyurethanes andthe like.

Suitable wood pulp fibers can be obtained from well-known chemicalprocesses such as the Kraft and sulfite processes. It is especiallypreferred to derive these wood pulp fibers from southern soft woods dueto their premium absorbency characteristics. These wood pulp fibers canalso be obtained from mechanical processes, such as ground wood, refinermechanical, thermomechanical, chemimechanical, and chemithermomechanicalpulp processes. Recycled or secondary wood pulp fibers, as well asbleached and unbleached wood pulp fibers, can be used.

Another type of hydrophilic fiber for use in the present invention ischemically stiffened cellulosic fibers. As used herein, the term“chemically stiffened cellulosic fibers” means cellulosic fibers thathave been stiffened by chemical means to increase the stiffness of thefibers under both dry and aqueous conditions. Such means can include theaddition of a chemical stiffening agent that, for example, coats and/orimpregnates of the fibers. Such means can also include the stiffening ofthe fibers by altering the chemical structure, e.g., by crosslinkingpolymer chains.

Where fibers are used as the absorbent layer (or a constituent componentthereof), the fibers can optionally be combined with a thermoplasticmaterial. Upon melting, at least a portion of this thermoplasticmaterial migrates to the intersections of the fibers, typically due tointerfiber capillary gradients. These intersections become bond sitesfor the thermoplastic material. When cooled, the thermoplastic materialsat these intersections solidify to form the bond sites that hold thematrix or web of fibers together in each of the respective layers. Thiscan be beneficial in providing additional overall integrity to thecleaning pad.

Amongst its various effects, bonding at the fiber intersectionsincreases the overall compressive modulus and strength of the resultingthermally bonded member. In the case of the chemically stiffenedcellulosic fibers, the melting and migration of the thermoplasticmaterial also has the effect of increasing the average pore size of theresultant web, while maintaining the density and basis weight of the webas originally formed. This can improve the fluid acquisition propertiesof the thermally bonded web upon initial exposure to fluid, due toimproved fluid permeability, and upon subsequent exposure, due to thecombined ability of the stiffened fibers to retain their stiffness uponwetting and the ability of the thermoplastic material to remain bondedat the fiber intersections upon wetting and upon wet compression. Innet, thermally bonded webs of stiffened fibers retain their originaloverall volume, but with the volumetric regions previously occupied bythe thermoplastic material becoming open to thus increase the averageinterfiber capillary pore size.

Thermoplastic materials useful in the present invention can be in any ofa variety of forms including particulates, fibers, or combinations ofparticulates and fibers. Thermoplastic fibers are a particularlypreferred form because of their ability to form numerous interfiber bondsites. Suitable thermoplastic materials can be made from anythermoplastic polymer that can be melted at temperatures that will notextensively damage the fibers that comprise the primary web or matrix ofeach layer. Preferably, the melting point of this thermoplastic materialwill be less than about 190° C., and preferably between about 75° C. andabout 175° C. In any event, the melting point of this thermoplasticmaterial should be no lower than the temperature at which the thermallybonded absorbent structures, when used in the cleaing pads, are likelyto be stored. The melting point of the thermoplastic material istypically no lower than about 50° C.

The thermoplastic materials, and in particular the thermoplastic fibers,can be made from a variety of thermoplastic polymers, includingpolyolefins such as polyethylene (e.g., PULPEX®) and polypropylene,polyesters, copolyesters, polyvinyl acetate, polyethylvinyl acetate,polyvinyl chloride, polyvinylidene chloride, polyacrylics, polyamides,copolyamides, polystyrenes, polyurethanes and copolymers of any of theforegoing such as vinyl chloride/vinyl acetate, and the like. Dependingupon the desired characteristics for the resulting thermally bondedabsorbent member, suitable thermoplastic materials include hydrophobicfibers that have been made hydrophilic, such as surfactant-treated orsilica-treated thermoplastic fibers derived from, for example,polyolefins such as polyethylene or polypropylene, polyacrylics,polyamides, polystyrenes, polyurethanes and the like. The surface of thehydrophobic thermoplastic fiber can be rendered hydrophilic by treatmentwith surfactant, such as a nonionic and/or anionic surfactant, e.g., byspraying the fiber with surfactant, by dipping the fiber into asurfactant or by including the surfactant as part of the polymer melt inproducing the thermoplastic fiber. Upon melting and resolidification,the surfactant will tend to remain at the surfaces of the thermoplasticfiber. Suitable surfactants include nonionic surfactants such as Brij®76 manufactured by ICI Americas, Inc. of Wilmington, Del., and varioussurfactants sold under the Pegosperse® trademark by Glyco Chemical, Inc.of Greenwich, Conn. Besides nonionic surfactants, anionic surfactantscan also be used. These surfactants can be applied to the thermoplasticfibers at levels of, for example, from about 0.2 to about 1 g. per sq.of centimeter of thermoplastic fiber.

Suitable thermoplastic fibers can be made from a single polymer(monocomponent fibers), or can be made from more than one polymer (e.g.,bicomponent fibers). As used herein, “bicomponent fibers” refers tothermoplastic fibers that comprise a core fiber made from one polymerthat is encased within a thermoplastic sheath made from a differentpolymer. The polymer comprising the sheath often melts at a different,typically lower, temperature than the polymer comprising the core. As aresult, these bicomponent fibers provide thermal bonding due to meltingof the sheath polymer, while retaining the desirable strengthcharacteristics of the core polymer.

Suitable bicomponent fibers for use herein can include sheath/corefibers having the following polymer combinations:polyethylene/polypropylene, polyethylvinyl acetate/polypropylene,polyethylene/polyester, polypropylene/polyester, copolyester/polyester,and the like. Particularly suitable bicomponent thermoplastic fibers foruse herein are those having a polypropylene or polyester core, and alower melting copolyester, polyethylvinyl acetate or polyethylene sheath(e.g., those available from Danaklon a/s, Chisso Corp., and CELBOND®,available from Hercules). These bicomponent fibers can be concentric oreccentric. As used herein, the terms “concentric” and “eccentric” referto whether the sheath has a thickness that is even, or uneven, throughthe cross-sectional area of the bicomponent fiber. Eccentric bicomponentfibers can be desirable in providing more compressive strength at lowerfiber thicknesses.

Methods for preparing thermally bonded fibrous materials are describedin co-pending U.S. application Ser. No. 08/479,096 (Richards et al.),filed Jul. 3, 1995 (see especially pages 16–20) and U.S. Pat. No.5,549,589 (Horney et al.), issued Aug. 27, 1996 (see especially Columns9 to 10). The disclosure of both of these references are incorporated byreference herein.

The absorbent layer can also comprise a HIPE-derived hydrophilic,polymeric foam that does not have the high absorbency of those describedabove as “superabsorbent materials”. Such foams and methods for theirpreparation are described in U.S. Pat. No. 5,550,167 (DesMarais), issuedAug. 27, 1996; and commonly assigned copending U.S. patent applicationSer. No. 08/370,695 (Stone et al.), filed Jan. 10, 1995 (both of whichare incorporated by reference herein).

The absorbent layer of the cleaning pad can be comprised of ahomogeneous material, such as a blend of cellulosic fibers (optionablythermally bonded) and swellable superabsorbent gelling polymer.Alternatively, the absorbent layer can be comprised of discrete layersof material, such as a layer of thermally bonded airlaid material and adiscrete layer of a superabsorbent material. For example, a thermallybonded layer of cellulosic fibers can be located lower than (i.e.,beneath) the superabsorbent material (i.e., between the superabsorbentmaterial and the scrubbing layer). In order to achieve high absorptivecapacity and retention of fluids under pressure, while at the same timeproviding initial delay in fluid uptake, it may be preferable to utilizesuch discrete layers when forming the absorbent layer. In this regard,the superabsorbent material can be located remote from the scrubbinglayer by including a less absorbent layer as the lower-most aspect ofthe absorbent layer. For example, a layer of cellulosic fibers can belocated lower (i.e., beneath) than the superabsorbent material (i.e.,between the superabsorbent material and the scrubbing layer).

In a preferred embodiment, the absorbent layer will comprise a thermallybonded airlaid web of cellulose fibers (Flint River, available fromWeyerhaeuser, Wash.) and AL Thermal C (thermoplastic available fromDanaklon a/s, Varde, Denmark), and a swellable hydrogel-formingsuperabsorbent polymer. The superabsorbent polymer is preferablyincorporated such that a discrete layer is located near the surface ofthe absorbent layer which is remote from the scrubbing layer.Preferably, a thin layer of, e.g., cellulose fibers (optionallythermally bonded) are positioned above the superabsorbent gellingpolymer to enhance containment.

B. Optional, but Preferred Scrubbing Layer

The scrubbing layer is the portion of the cleaning pad that contacts thesoiled surface during cleaning. As such, materials useful as thescrubbing layer are preferably sufficiently durable that the layer willretain its integrity during the cleaning process. In addition, when thecleaning pad is used in combination with a solution, the scrubbing layeris preferably capable of absorbing liquids and soils, and relinquishingthose liquids and soils to the absorbent layer. This will ensure thatthe scrubbing layer will continually be able to remove additionalmaterial from the surface being cleaned. Whether the implement is usedwith a cleaning solution (i.e., in the wet state) or without cleaningsolution (i.e., in the dry state), the scrubbing layer will, in additionto removing particulate matter, facilitate other functions, such aspolishing, dusting, and buffing the surface being cleaned.

The scrubbing layer can be a monolayer, or a multi-layer structure oneor more of whose layers can be slitted to faciliate the scrubbing of thesoiled surface and the uptake of particulate matter. This scrubbinglayer, as it passes over the soiled surface, interacts with the soil(and cleaning solution when used), loosening and emulsifying tough soilsand permitting them to pass freely into the absorbent layer of the pad.The scrubbing layer preferably contains openings (e.g., slits) thatprovide an easy avenue for larger particulate soil to move freely in andbecome entrapped within the absorbent layer of the pad. Low densitystructures are preferred for use as the scrubbing layer, to facilitatetransport of particulate matter to the pad's absorbent layer.

In order to provide desired integrity, materials particularly suitablefor the scrubbing layer include synthetics such as polyolefins (e.g.,polyethylene and polypropylene), polyesters, polyamides, syntheticcellulosics (e.g., RAYON®), and blends thereof. Such synthetic materialscan be manufactured using a known process such as carded, spunbond,meltblown, airlaid, needlepunched and the like.

C. Optional Attachment Layer

The cleaning pads of the present invention can optionally have anattachment layer that allows the pad to be connected to an implement'shandle or the support head in preferred implements. The attachment layerwill be necessary in those embodiments where the absorbent layer is notsuitable for attaching the pad to the support head of the handle. Theattachment layer can also function as a means to prevent fluid flowthrough the top surface (i.e., the handle-contacting surface) of thecleaning pad, and can further provide enhanced integrity of the pad. Aswith the scrubbing and absorbent layers, the attachment layer canconsist of a mono-layer or a multi-layer structure, so long as it meetsthe above requirements.

In a preferred embodiment of the present invention, the attachment layerwill comprise a surface which is capable of being mechanically attachedto the handle's support head by use of known hook and loop technology.In such an embodiment, the attachment layer will comprise at least onesurface which is mechanically attachable to hooks that are permanentlyaffixed to the bottom surface of the handle's support head.

To achieve the desired fluid imperviousness and attachability, it ispreferred that a laminated structure comprising, e.g., a meltblown filmand fibrous, nonwoven structure be utilized. In a preferred emodiment,the attachment layer is a tri-layered material having a layer ofmeltblown polypropylene film located between two layers of spun-bondedpolypropylene.

D. Optional, but Preferred, Multiple Planar Surfaces

While the ability of the cleaning pad to absorb and retain fluids hasbeen determined to be important to hard surface cleaning performance(see, e.g., copending U.S. patent application Ser. No. 08/756,507 (Holtet al.), copending U.S. patent application Ser. No. 08/756,864 (Sherryet al.), and copending U.S. patent application Ser. No. 08/756,999 (Holtet al.), all filed Nov. 26, 1996 and incorporated by reference herein.),preferred performance can be achieved by properly defining the overallstructure of the cleaning pad. In particular, pads having an essentiallyflat floor contacting surface (i.e., essentially one planar surface forcontacting the soiled surface during cleaning) do not provide the bestperformance because soil tends to build up on the leading edge, whichalso is the main point where the cleaning solution is transferred to theabsorbent layer.

The preferred pads provide multiple planar surfaces during cleaning andprovide enhanced performance. Referring to FIG. 2 in the drawings,cleaning pad 100 is depicted as having an upper surface 103 that allowsthe pad to be releasably attached to a handle. Cleaning pad 100 also hasa lower surface depicted generally as 110 which contacts the floor orother hard surface during cleaning. This lower surface 110 actuallyconsists of 3 substantially planar surfaces 112, 114 and 116. Asdepicted, the planes corresponding to surfaces 112 and 116 intersect theplane corresponding to surface 114. Thus, when an implement to which pad100 is attached is moved from rest in the direction indicated by Y_(f),friction causes pad 100 to “rock” such that lower surface 112 contactsthe surface being cleaned. As the movement in the Y_(f) directiondiminishes, lower surface 114 will then contact the surface beingcleaned. As the implement and pad are moved from rest in the Y_(b)direction, friction causes pad 100 to rock such that lower surface 116then contacts the surface being cleaned. As this cleaning motion isrepeated, the portion of the pad contacting the soiled surface areconstantly changing.

It is believed that the enhanced cleaning of the preferred pads isin-part due to the “lifting” action that results from the back and forthmotion during cleaning. In particular, when the cleaning motion in onedirection is stopped and the forces exerted on the implement allow pad100 to “rock” such that the surface-contacting planar surface moves fromsurface 112 (or 116) to surface 114, soil is moved in an an upwarddirection.

The cleaning pad of the present invention should be capable of retainingabsorbed fluid, even during the pressures exerted during the cleaningprocess. This is referred to herein as the cleaning pad's ability toavoid “squeeze-out” of absorbed fluid, or conversely its ability toretain absorbed fluid under pressure. The method for measuringsqueeze-out is described in the Test Methods section. Briefly, the testmeasures the ability of a saturated cleaning pad to retain fluid whensubjected to a pressure of 0.25 psi. Preferably, the cleaning pads ofthe present invention will have a squeeze-out value of not more thanabout 40%, more preferably not more than about 25%, still morepreferably not more than about 15%, and most preferably not more thanabout 10%.

III. Cleaning Implements

The detergent compositions described above can be desirably used with animplement for cleaning a surface, the implement comprising:

-   -   a. a handle; and    -   b. a removable cleaning pad containing an effective amount of a        superabsorbent material, and having a plurality of substantially        planar surfaces, wherein each of the substantially planar        surfaces contacts the surface being cleaned, more preferably        said pad is a removable cleaning pad having a length and a        width, the pad comprising    -   i. a scrubbing layer; and    -   ii. an absorbent layer comprising a first layer and a second        layer, where the first layer is located between the scrubbing        layer and the second layer (i.e., the first layer is below the        second layer) and has a smaller width than the second layer.

An important aspect of the cleaning performance provided by thepreferred pad is related to the ability to provide multiple planarsurfaces that contact the soiled surface during the cleaning operation.In the context of a cleaning implement such as a mop, these planarsurfaces are provided such that during the typical cleaning operation(i.e., where the implement is moved back and forth in a directionsubstantially parallel to the pad's Y-dimension or width), each of theplanar surfaces contact the surface being cleaned as a result of“rocking” of the cleaning pad. This aspect of the invention, and thebenefits provided, are discussed in detail with reference to thedrawings.

The skilled artisan will recognize that various materials can beutilized to carry out the claimed invention. Thus, while preferredmaterials are described below for the various implement and cleaning padcomponents, it is recognized that the scope of the invention is notlimited to such disclosures.

a. The Handle

The handle of the above cleaning implement can be any material that willfacilitate gripping of the cleaning implement. The handle of thecleaning implement will preferably comprise any elongated, durablematerial that will provide practical cleaning. The length of the handlewill be dictated by the end-use of the implement.

The handle will preferably comprise at one end a support head to whichthe cleaning pad can be releasably attached. To facilitate ease of use,the support head can be pivotably attached to the handle using knownjoint assemblies. Any suitable means for attaching the cleaning pad tothe support head can be utilized, so long as the cleaning pad remainsafixed during the cleaning process. Examples of suitable fastening meansinclude clamps, hooks & loops (e.g., VELCRO®), and the like. In apreferred embodiment, the support head will comprise hooks on its lowersurface that will mechanically attach to the upper layer (preferably adistinct attachment layer) of the absorbent cleaning pad.

A preferred handle, comprising a fluid dispensing means, is depicted inFIG. 1 and is fully described in co-pending U.S. patent application Ser.No. 08/756,774, filed Nov. 15, 1996 by V. S. Ping, et al. (Case 6383),which is incorporated by reference herein. Another preferred handle,which does not contain a fluid dispensing means, is depicted in FIGS. 1a and 1 b, and is fully described in co-pending U.S. patent applicationSer. No. 08/716,755, filed Sep. 23, 1996 by A. J. Irwin (P&G Case 6262),which is incorporated by reference herein.

b. The Cleaning Pad

The cleaning pads described hereinbefore can be used without attachmentto a handle, or as part of the above cleaning implement. They cantherefore be constructed without the need to be attachable to a handle,i.e., such that they can be used either in combination with the handleor as a stand-alone product. As such, it can be preferred to prepare thepads with an optional attachment layer as described hereinbefore. Withthe exception of an attachment layer, the pads themselves are asdescribed above.

As used herein, the term “direct fluid communication” means that fluidcan transfer readily between two cleaning pad components or layers(e.g., the scrubbing layer and the absorbent layer) without substantialaccumulation, transport, or restriction by an interposed layer. Forexample, tissues, nonwoven webs, construction adhesives, and the likecan be present between the two distinct components while maintaining“direct fluid communication”, as long as they do not substantiallyimpede or restrict fluid as it passes from one component or layer toanother.

As used herein, the term “Z-dimension” refers to the dimensionorthogonal to the length and width of the cleaning pad of the presentinvention, or a component thereof. The Z-dimension usually correspondsto the thickness of the cleaning pad or a pad component.

As used herein, the term “X-Y dimension” refers to the plane orthogonalto the thickness of the cleaning pad, or a component thereof. The X andY dimensions usually correspond to the length and width, respectively,of the cleaning pad or a pad component. In general, when the cleaningpad is used in conjunction with a handle, the implement will be moved ina direction parallel to Y-dimension of the pad. (See the discussionbelow.)

As used herein, the term “layer” refers to a member or component of acleaning pad whose primary dimension is X-Y, i.e., along its length andwidth. It should be understood that the term layer is not necessarilylimited to single layers or sheets of material. Thus the layer cancomprise laminates or combinations of several sheets or webs of therequisite type of materials. Accordingly, the term “layer” includes theterms “layers” and “layered.”

As used herein, the term “hydrophilic” is used to refer to surfaces thatare wettable by aqueous fluids deposited thereon. Hydrophilicity andwettability are typically defined in terms of contact angle and thesurface tension of the fluids and solid surfaces involved. This isdiscussed in detail in the American Chemical Society publicationentitled Contact Angle, Wettability and Adhesion, edited by Robert F.Gould (Copyright 1964), which is hereby incorporated herein byreference. A surface is said to be wetted by a fluid (i.e., hydrophilic)when either the contact angle between the fluid and the surface is lessthan 90°, or when the fluid tends to spread spontaneously across thesurface, both conditions normally co-existing. Conversely, a surface isconsidered to be “hydrophobic” if the contact angle is greater than 90°and the fluid does not spread spontaneously across the surface.

As used herein, the term “scrim” means any durable material thatprovides texture to the surface-contacting side of the cleaning pad'sscrubbing layer, and also has a sufficient degree of openness to allowthe requisite movement of fluid to the absorbent layer of the cleaningpad. Suitable materials include materials that have a continuous, openstructure, such as synthetic and wire mesh screens. The open areas ofthese materials can be readily controlled by varying the number ofinterconnected strands that comprise the mesh, by controlling thethickness of those interconnected strands, etc. Other suitable materialsinclude those where texture is provided by a discontinous patternprinted on a substrate. In this aspect, a durable material (e.g., asynthetic) can be printed on a substrate in a continuous ordiscontinuous pattern, such as individual dots and/or lines, to providethe requisite texture. Similarly, the continuous or discontinuouspattern can be printed onto a release material that will then act as thescrim. These patterns can be repeating or they can be random. It will beunderstood that one or more of the approaches described for providingthe desired texture can be combined to form the optional scrim material.The Z direction height and open area of the scrim and or scrubbingsubstrate layer help to control and or retard the flow of liquid intothe absorbent core material. The Z height of the scrim and or scrubbingsubstrate help provide a means of controlling the volume of liquid incontact with the cleaning surface while at the same time controlling therate of liquid absorption, fluid communication into the absorption corematerial.

For purposes of the present invention, an “upper” layer of a cleaningpad is a layer that is relatively further away from the surface that isto be cleaned (i.e., in the implement context, relatively closer to theimplement handle during use). The term “lower” layer conversely means alayer of a cleaning pad that is relatively closer to the surface that isto be cleaned (i.e., in the implement context, relatively further awayfrom the implement handle during use). As such, the scrubbing layer isthe lower-most layer and the absorbent layer is an upper layer relativeto the scrubber layer. The terms “upper” and “lower” are similarly usedwhen referring to layers that are multi-ply (e.g., when the scrubbinglayer is a two-ply material). The terms “above” and “below” are used todescribe relative locations of two or more materials in a cleaning pad'sthickness. By way of illustration, a material A is “above” material B ifmaterial B is positioned closer to the scrubbing layer than material A.Similarly, material B is “below” material material A in thisillustration.

All percentages, ratios and proportions used herein are by weight unlessotherwise specified and all numerical limits are the normalapproximations within normal limits of accuracy.

IV. Other Embodiments of the Cleaning Pad

To enhance the pad's ability to remove tough soil residues and increasethe amount of cleaning fluid in contact with the cleaning surface, itcan be desirable to incorporate a scrim material into the cleaning pad.The scrim will be comprised of a durable, tough material that willprovide texture to the pad's scrubbing layer, particularly when in-usepressures are applied to the pad. Preferably, the scrim will be locatedsuch that it is in close proximity to the surface being cleaned. Thus,the scrim can be incorporated as part of the scrubbing layer or theabsorbent layer; or it can be included as a distinct layer, preferablypositioned between the scrubbing and absorbent layers. In one preferredembodiment, where the scrim material is of the same X-Y dimension as theoverall cleaning pad, it is preferred that the scrim material beincorporated such that it does not directly contact, to a significantdegree, the surface being cleaned. This will maintain the ability of thepad to move readily across the hard surface and will aid in preventingnon-uniform removal of the cleaning solution employed. As such, if thescrim is part of the scrubbing layer, it will be an upper layer of thiscomponent. Of course, the scrim should at the same time be positionedsufficiently low in the pad to provide it's scrubbing function. Thus, ifthe scrim is incorporated as part of the absorbent layer, it will be alower layer thereof. In a separate embodiment, it can be desirable toplace the scrim such that it will be in direct contact with the surfaceto be cleaned.

In addition to the importance of properly positioning the scrim is thatthe scrim not significantly impede fluid flow through the pad. The scrimtherefore is a relatively open web.

The scrim material will be any material that can be processed to providea tough, open-textured web. Such materials include polyolefins (e.g.,polyethylene, polypropylene), polyesters, polyamides, and the like. Theskilled artisan will recognize that these different materials exhibit adifferent degree of hardness. Thus, the hardness of the scrim materialcan be controlled, depending on the end-use of the pad/implement. Wherethe scrim is incorporated as a discrete layer, many commercial sourcesof such materials are available (e.g., design number VO1230, availablefrom Conwed Plastics, Minneapolis, Minn.). Alternatively, the scrim canbe incorporated by printing a resin or other synthetic material (e.g.latex) onto a substrate, such as is disclosed in U.S. Pat. No.4,745,021, issued May 17, 1988 to Ping, III et al., and U.S. Pat. No.4,733,774, issued Mar. 29, 1988 to Ping, III et al., both of which areincorporated by reference herein.

The various layers that comprise the cleaning pad can be bonded togetherutilizing any means that provides the pad with sufficient integrityduring the cleaning process. The scrubbing and attachment layers can bebonded to the absorbent layer or to each other by any of a variety ofbonding means, including the use of a uniform continuous layer ofadhesive, a patterned layer of adhesive or any array of separate lines,spirals or spots of adhesive. Alternatively, the bonding means cancomprise heat bonds, pressure bonds, ultrasonic bonds, dynamicmechanical bonds or any other suitable bonding means or combinations ofthese bonding means as are known in the art. Bonding can be around theperimeter of the cleaning pad (e.g., heat sealing the scrubbing layerand optional attachment layer and/or scrim material), and/or across thearea (i.e., the X-Y plane) of the cleaning pad so as to form a patternon the surface of the cleaning pad. Bonding the layers of the cleaningpad with ultrasonic heating to form bonds across the area of the padwill provide integrity to avoid shearing of the discrete pad layersduring use.

Referring to the figures which depict the cleaning pad of the presentinvention, FIG. 3 is a perspective view of a removable cleaning pad 200comprising a scrubbing layer 201, an attachment layer 203 and anabsorbent layer 205 positioned between the scrubbing layer and theattachment layer. Cleaning pad 200 is not depicted as having multiplesubstantially planar surfaces. As indicated above, while FIG. 3 depictseach of layers 201, 203 and 205 as a single layer of material, one ormore of these layers can consist of a laminate of two or more plies. Forexample, in a preferred embodiment, scrubbing layer 201 is a two-plylaminate of carded polypropylene, where the lower layer is slitted.Also, though not depicted in FIG. 3, materials that do not inhibit fluidflow can be positioned between scrubbing layer 201 and absorbent layer203 and/or between absorbent layer 203 and attachment layer 205.However, it is important that the scrubbing and absorbent layers be insubstantial fluid communication, to provide the requisite absorbency ofthe cleaning pad. While FIG. 3 depicts pad 200 as having all of thepad's layers of equal size in the X and Y dimensions, it is preferredthat the scrubbing layer 201 and attachment layer 205 be larger than theabsorbent layer, such that layers 201 and 205 can be bonded togetheraround the periphery of the pad to provide integrity. The scrubbing andattachment layers can be bonded to the absorbent layer or to each otherby any of a variety of bonding means, including the use of a uniformcontinuous layer of adhesive, a patterned layer of adhesive or any arrayof separate lines, spirals or spots of adhesive. Alternatively, thebonding means can comprise heat bonds, pressure bonds, ultrasonic bonds,dynamic mechanical bonds or any other suitable bonding means orcombinations of these bonding means as are known in the art. Bonding canbe around the perimeter of the cleaning pad, and/or across the surfaceof the cleaning pad so as to form a pattern on the surface of thescrubbing layer 201.

FIG. 4 is a blown perspective view of the absorbent layer 305 of anembodiment of a cleaning pad of the present invention. The cleaningpad's scrubbing layer and optional attachment layer are not shown inFIG. 4. Absorbent layer 305 is depicted in this embodiment as consistingof a tri-laminate structure. Specifically absorbent layer 305 is shownto consist of a discrete layer of particulate superabsorbent gellingmaterial, shown as 307, positioned between two discrete layers 306 and308 of fibrous material. In this embodiment, because of the region 307of high concentration of superabsorbent gelling material, it ispreferred that the superabsorbent material not exhibit gel blockingdiscussed above. In a particularly preferred embodiment, fibrous layers306 and 308 will each be a thermally bonded fibrous substrate ofcellulosic fibers, and lower fibrous layer 308 will be in direct fluidcommunication with the scrubbing layer (not shown). (Layer 307 canalternatively be a mixture of fibrous material and superabsorbentmaterial, where the superabsorbent material is preferably present in arelatively high percentage by weight of the layer.) Also, while depictedas having equal widths, in a preferred embodiment layer 306 will bewider than layer 307 and layer 307 will be wider than layer 308. When ascrubbing and attachment layer are included, such a combination willprovide a pad having the multiple substantially planar surfaces of thepresent invention.

FIG. 5 is a cross-sectional view (taken along the y-z plane) of cleaningpad 400 having a scrubbing layer 401, an attachement layer 403, and anabsorbent layer indicated generally as 404 positioned between thescrubbing and attachment layers. Absorbent layer 404 consists of threeseparate layers 405, 407 and 409. Layer 409 is wider than layer 407which is wider than layer 405. Again, this tapering of absorbent layermaterials provides multiple planar surfaces indicated generally as 411,413 and 415. (For purposes of discussion, surface 411 is referred to asthe front edge of the cleaning pad 400 when the pad is attached to animplement; surface 413 is referred to as the back edge of pad 400.) Inone embodiment, layers 405 and 407 comprise a high concentration ofsuperabsorbent material, while layer 409 contains little or nosuperabsorbent material. In such embodiments, one or both of layers 405and 407 can be comprised of a homogenous blend of superabsorbentmaterial and fibrous material. Alternatively, one or both layers can becomprised of discrete layers, e.g., two fibrous layers surrounding anessentially continuous layer of superabsorbent particles.

Though not a requirement, Applicants have found that it can be desirableto reduce the level of or eliminate superabsorbent particles at theextreme front and rear edges. This accomplished in pad 400 byconstructing absorbent layer 409 without superabsorbent material.

V. Test Methods

A. Performance Under Pressure

This test determines the gram/gram absorption of deionized water for acleaning pad that is laterally confined in a piston/cylinder assemblyunder an initial confining pressure of 0.09 psi (about 0.6 kPa).(Depending on the composition of the cleaning pad sample, the confiningpressure can decrease slightly as the sample absorbs water and swellsduring the time of the test.) The objective of the test is to assess theability of a cleaning pad to absorb fluid, over a practical period oftime, when the pad is exposed to usage conditions (horizontal wickingand pressures).

The test fluid for the PUP capacity test is deionized water. This fluidis absorbed by the cleaning pad under demand absorption conditions atnear-zero hydrostatic pressure.

A suitable apparatus 510 for this test is shown in FIG. 5. At one end ofthis apparatus is a fluid reservoir 512 (such as a petri dish) having acover 514. Reservoir 512 rests on an analytical balance indicatedgenerally as 516. The other end of apparatus 510 is a fritted funnelindicated generally as 518, a piston/cylinder assembly indicatedgenerally as 520 that fits inside funnel 518, and cylindrical plasticfritted funnel cover indicated generally as 522 that fits over funnel518 and is open at the bottom and closed at the top, the top having apinhole. Apparatus 510 has a system for conveying fluid in eitherdirection that consists of sections glass capillary tubing indicated as524 and 531 a, flexible plastic tubing (e.g., ¼ inch i.d. and ⅜ incho.d. Tygon tubing) indicated as 531 b, stopcock assemblies 526 and 538and Teflon connectors 548, 550 and 552 to connect glass tubing 524 and531 a and stopcock assemblies 526 and 538. Stopcock assembly 526consists of a 3-way valve 528, glass capillary tubing 530 and 534 in themain fluid system, and a section of glass capillary tubing 532 forreplenishing reservoir 512 and forward flushing the fritted disc infritted funnel 518. Stopcock assembly 538 similarly consists of a 3-wayvalve 540, glass capillary tubing 542 and 546 in the main fluid line,and a section of glass capillary tubing 544 that acts as a drain for thesystem.

Referring to FIG. 6, assembly 520 consists of a cylinder 554, a cup-likepiston indicated by 556 and a weight 558 that fits inside piston 556.Attached to bottom end of cylinder 554 is a No. 400 mesh stainless steelcloth screen 559 that is biaxially stretched to tautness prior toattachment. The cleaning pad sample indicated generally as 560 rests onscreen 559 with the surface-contacting (or scrubbing) layer in contactwith screen 559. The cleaning pad sample is a circular sample having adiameter of 5.4 cm. (While sample 560 is depicted as a single layer, thesample will actually consist of a circular sample having all layerscontained by the pad from which the sample is cut.) Cylinder 554 isbored from a transparent LEXAN® rod (or equivalent) and has an innerdiameter of 6.00 cm (area=28.25 cm²), with a wall thickness ofapproximately 5 mm and a height of approximately 5 cm. The piston 556 isin the form of a Teflon cup and is machined to fit into cylinder 554within tight tolerances. Cylindrical stainless steel weight 558 ismachined to fit snugly within piston 556 and is fitted with a handle onthe top (not shown) for ease in removing. The combined weight of piston556 and weight 558 is 145.3 g, which corresponds to a pressure of 0.09psi for an area of 22.9 cm².

The components of apparatus 510 are sized such that the flow rate ofdeionized water therethrough, under a 10 cm hydrostatic head, is atleast 0.01 g/cm²/sec, where the flow rate is normalized by the area offritted funnel 518. Factors particularly impactful on flow rate are thepermeability of the fritted disc in fritted funnel 518 and the innerdiameters of glass tubing 524, 530, 534, 542, 546 and 531 a, andstopcock valves 528 and 540.

Reservoir 512 is positioned on an analytical balance 516 that isaccurate to at least 0.01 g with a drift of less than 0.1 g/hr. Thebalance is preferably interfaced to a computer with software that can(i) monitor balance weight change at pre-set time intervals from theinitiation of the PUP test and (ii) be set to auto initiate on a weightchange of 0.01–0.05 g, depending on balance sensitivity. Capillarytubing 524 entering the reservoir 512 should not contact either thebottom thereof or cover 514. The volume of fluid (not shown) inreservoir 512 should be sufficient such that air is not drawn intocapillary tubing 524 during the measurement. The fluid level inreservoir 512, at the initiation of the measurement, should beapproximately 2 mm below the top surface of fritted disc in frittedfunnel 518. This can be confirmed by placing a small drop of fluid onthe fritted disc and gravimetrically monitoring its slow flow back intoreservoir 512. This level should not change significantly whenpiston/cylinder assembly 520 is positioned within funnel 518. Thereservoir should have a sufficiently large diameter (e.g., ˜14 cm) sothat withdrawal of ˜40 ml portions results in a change in the fluidheight of less than 3 mm.

Prior to measurement, the assembly is filled with deionized water. Thefritted disc in fritted funnel 518 is forward flushed so that it isfilled with fresh deionized water. To the extent possible, air bubblesare removed from the bottom surface of the fritted disc and the systemthat connects the funnel to the reservoir. The following procedures arecarried out by sequential operation of the 3-way stopcocks:

-   -   1. Excess fluid on the upper surface of the fritted disc is        removed (e.g. poured) from fritted funnel 518.    -   2. The solution height/weight of reservoir 512 is adjusted to        the proper level/value.    -   3. Fritted funnel 518 is positioned at the correct height        relative to reservoir 512.    -   4. Fritted funnel 518 is then covered with fritted funnel cover        522.    -   5. The reservoir 512 and fritted funnel 518 are equilibrated        with valves 528 and 540 of stopcock assemblies 526 and 538 in        the open connecting position.    -   6. Valves 528 and 540 are then closed.    -   7. Valve 540 is then turned so that the funnel is open to the        drain tube 544.    -   8. The system is allowed to equilibrate in this position for 5        minutes.    -   9. Valve 540 is then returned to its closed position.

Steps Nos. 7–9 temporarily “dry” the surface of fritted funnel 518 byexposing it to a small hydrostatic suction of ˜5 cm. This suction isapplied if the open end of tube 544 extends ˜5 cm below the level of thefritted disc in fritted funnel 518 and is filled with deionized water.Typically ˜0.04 g of fluid is drained from the system during thisprocedure. This procedure prevents premature absorption of deionizedwater when piston/cylinder assembly 520 is positioned within frittedfunnel 518. The quantity of fluid that drains from the fritted funnel inthis procedure (referred to as the fritted funnel correction weight, or“Wffc”)) is measured by conducting the PUP test (see below) for a timeperiod of 20 minutes without piston/cylinder assembly 520. Essentiallyall of the fluid drained from the fritted funnel by this procedure isvery quickly reabsorbed by the funnel when the test is initiated. Thus,it is necessary to subtract this correction weight from weights of fluidremoved from the reservoir during the PUP test (see below).

A round die-cut sample 560 is placed in cylinder 554. The piston 556 isslid into cylinder 554 and positioned on top of the cleaning pad sample560. The piston/cylinder assembly 520 is placed on top of the fritportion of funnel 518, the weight 558 is slipped into piston 556, andthe top of funnel 518 is then covered with fritted funnel cover 522.After the balance reading is checked for stability, the test isinitiated by opening valves 528 and 540 so as to connect funnel 518 andreservoir 512. With auto initiation, data collection commencesimmediately, as funnel 518 begins to reabsorb fluid.

Data is recorded at intervals over a total time period of 1200 seconds(20 minutes). PUP absorbent capacity is determined as follows:t ₁₂₀₀absorbent capacity(g/g)=[Wr _((t=0)) −Wr _((t=1200)) −Wffc]/Wdswhere t₁₂₀₀ absorbent capacity is the g/g capacity of the pad after 1200seconds, Wr_((t=0)) is the weight in grams of reservoir 512 prior toinitiation, Wr_((t=1200)) is the weight in grams of reservoir 512 at1200 seconds after initiation, Wffc is the fritted funnel correctionweight and Wds is the dry weight of the cleaning pad sample. It followsthat the sample's t₃₀ and t₉₀₀ absorbent capacities are measuredsimilarly, except Wr_((t=30)) and Wr_((t=900)) (i.e., the weight of thereservoir at 30 seconds and 900 seconds after initiation, respectively)are used in the above formula. The t₃₀ percent absorbency of the sampleis calculated as [t₃₀ absorbent capacity]/[t₁₂₀₀ absorbentcapacity]×100%.

B. Squeeze-out

The ability of the cleaning pad to retain fluid when exposed to in-usepressures, and therefor to avoid fluid “squeeze-out”, is anotherimportant parameter to the present invention. “Squeeze-out” is measuredon an entire cleaning pad by determining the amount of fluid that can beblotted from the sample with Whatman filter paper under pressures of0.25 psi (1.5 kPa). Squeeze-out is performed on a sample that has beensaturated to capacity with deionized water via horizontal wicking(specifically, via wicking from the surface of the pad consisting of thescrubbing or surface-contacting layer). (One means for obtaining asaturated sample is described as the Horizontal Gravimetric Wickingmethod of U.S. application Ser. No. 08/542,497 (Dyer et al.), filed Oct.13, 1995, which is incorporated by reference herein.) Thefluid-containing sample is placed horizontally in an apparatus capableof supplying the respective pressures, preferably by using an air-filledbag that will provide evenly distributed pressure across the surface ofthe sample. The squeeze-out value is reported as the weight of testfluid lost per weight of the wet sample.

EXAMPLES Context of Use with Absorbent Cleaning Pad

Detergent composition/solution containing about 0.12% of detergentsurfactant, comprising a linear alcohol ethoxylate detergent surfactant(Neodol 1-5®, available from Shell Chemical Co.) and an alkylsulfonate(Bioterge® PAS-8s, a linear C₈ sulfonate available from Stepan Co.);about 1%, ethanol (Quantum Chemicals), about 0.75% propylene glycoln-butyl ether (Dow Co.); about 0.006% Dow Corning AF suds suppressor(Dow) and about 0.05% 2-amino-2-methyl-1-propanol; adjuvents includingdyes and perfumes; and the balance deionized water is used as a base inwhich various polymers and gums are added for performance comparisons infloor end result cleaning. This testing is done in the context of anabsorbent cleaning pad (containing an effective amount of sodiumpolyacrylate, preferably cross-linked sodium polyacrylate, asuperabsorbent material).

Test Protocol

Testing involves soiling a 2′×2′ floor area each with about 8.0 ml of anoily particulate soil solution using a paint roller (about 0.5 g soilapplied to tile after solvent evaporated). Each floor area is thencleaned using 8 ml of solution (applied to bottom 2 tiles) and anabsorbent pad (disclosed within this filing) of the following dimensionapproximately 5.75″×5.75″. The cleaning pad is attached to a velcro mophead on a handle and wiped across the floor surface using an up-and-downmotion, going over the surface one way and then back the other way.Floors are then graded for end result cleaning appearance at differenttime intervals (about 10, 30, and 60 minutes). The tiles are thenre-soiled and a second cleaning test is run. In the second test, thesame soiled pads from the first test are used to simulate stresscleaning situation and determine the effect of build-up. The End ResultComparison is based upon a 0–4 Scale where 0 is none and 4 is severestreaks The following are examples of some of the data (grade differenceof 0.25 is significant):

TABLE 1 Example 7 Example 0.005% 4 Xanthan Example Example 0.15% ExampleExample Gum End Example 2 3 Polyvinyl 5 6 + Result 1 0.005% 0.015%Pyrolidone/ 0.05% 0.008% 0.008% Com- No Xanthan Xanthan AcrylicPolystyrene Polyvinyl Polyvinyl parison polymer gum Gum Acid SulfonatePyrolidone Pyrolidone Test 1 1.25 0.5 0.75 — — — — Test 2 — 0.5 — 1.751.25 — — Test 3 1.25 0.5 — — — 1.25 — Test 4 1.25 0.5 — — — — 0.75

TABLE 2 Example Example Example 8 9 13 0.08 0.08 0.005 Hydroxy HydroxyXanthan Example propyl propyl Example Example Gum End Example 2non-ionic cationic 10 Example 12 + Result 1 0.005 gum gum 0.08 11 0.0050.005 Com- No Xanthan Jaguar N Jaguar Gum 0.08 Poly Poly parison polymergum HP120 C-17 Arabic Pectin acrylate acrylate Test 5 1.25 0.75 — — — —1.5 — Test 6 1.25 0.5 — — — — — 1.0 Test 7 — 0.5 1.0 0.75 — — — — Test 81.75 0.75 — — 1.25 — — — Test 9 1.75 0.75 — — — 1.0 — —

The data in the Table 1 and 2 clearly shows the benefit of usingspecific polymers especially at low levels. Xanthan gum, Jaguars®polymers, Pectin and Gum Arabic are particularly impressive. Alsocomparing examples 6 vs 7 and example 12 vs 13 shows how Xanthan gum canwork synergistically with other polymers to provide an improvement.

The impact of polymers added to conventional cleaners diluted accordingto recommended dilution (using distilled water) but used in the contextof absorbent cleaning pad were tested using the protocol listed above.The indicated polymers and levels are used in Mr. Clean®, and Pinesol®(lemon), commercially available products. Results are as follows:

TABLE 3 Example 15 Example 17 Example 2 Example 14 Mr. Clean Example 16Pinesol Solution Base Mr. Clean All-purpose Pinesol Lemon End Resultfrom above + 0.005 All-purpose 0.75% dilution + 0.005 Lemon 1.5%dilution + 0.005 Comparison Xanthan gum 0.75% dilution Xanthan Gum 1.5%dilution Xanthan Gum Test 10 0.5 1.75 1.0 — — Test 11 0.75 — — 2.0 1.5

The data in Table 3 clearly shows that xanthan gum can improve the endresult of conventional floor cleaners when diluted to recommendeddilution and used in the context of the absorbent cleaning pad(disclosed in this filing).

Conventional Mop Testing

To further dimensionalize the benefit of hydrophilic polymers in thecontext of a conventional cleaner using conventional cleaningimplements, testing is done using the soiling protocol for the previoustesting. The implements used and application protocol are different asfollows:

Sponge Mop Simulation:

An approximately 2.5″×3.5″×1″ sponge is attached to handle soaked in theappropriate solution and wrung to dampness (about 60 ml solutionabsorbed in dry sponge). The sponge is then wiped across the soiledfloor surface in an up-and-down motion passing over the surface oncethan back in the other direction. Floors are then graded for end resultappearance after completely drying using 0–4 scale (0=best and 4=worst).

Strip Mop Simulation:

A Libman strip mop head is taken and strips are cut down to 4.75″lengths to form a mini strip mop. The mini strip mop head is then soakedin the appropriate solution and wrung to dampness (about 130 g solutionabsorbed in dry implement). Each mini strip mop head is then wipedacross the soiled floor surface in side-to-side motion, passing over theentire surface. The mini strip mop is then passed in an up-and-downmotion across the entire surface to simulate a wipe pattern used byconsumers when using a strip mop. The floors are then graded for endresult appearance after completely drying using the 0–4 scale.

Floor Cloth Simulation:

A European floor cloth (referred to as a Serpien) is cut to anapproximately 9″×10″ dimension. The floor cloth is then soaked in theappropriate solution and wrung to dampness about 70 g solution absorbedin dry implement). Using an approximately 5″×5″ flat mop head attachedto a handle the floor cloth is wiped across soiled floor surface in anup-and-down motion passing over surface once than back in the otherdirection. Floors are then graded for end result appearance aftercompletely drying using the 0–4 scale.

Commercially available conventional products Mr. Clean®, and Pinesol®(lemon) solutions are diluted according to recommended dilutioninstructions (using approximately 7 g tap water). These solutions arethen tested using the conventional mops with and without xanthan gum.

TABLE 4 Example 19 Example 21 Example 23 Example 18 Sponge Mop withExample 20 Strip Mop with Example 22 Floor Cloth with Sponge Mop withMr. Clean Strip Mop with Mr. Clean Floor Cloth with Mr. Clean Mr. CleanAll-purpose Mr. Clean All-purpose Mr. Clean All-purpose End ResultAll-purpose 0.75% dilution + 0.005 All-purpose 0.75% dilution + 0.005All-purpose 0.75% dilution + 0.005 Comparison 0.75% dilution Xanthan Gum0.75% dilution Xanthan Gum 0.75% dilution Xanthan Gum Test 12 3.0 1.75 —— — — Test 13 — — 1.5 1.0 — — Test 14 — — — — 2.0 1.5

TABLE 5 Example Example Example Example 24 25 26 27 End Result SpongeSponge Strip Strip Comparison Mop Mop Mop Mop with with with withPinesol Pinesol Pinesol Pinesol Lemon Lemon Lemon Lemon 1.5% 1.5% 1.5%1.5% dilution dilution + dilution dilution + 0.005 0.005 Xanthan XanthanGum Gum Test 15 3.0 2.5 — — Test 16 — — 2.25 1.75

The data in Tables 4 and 5 again shows that xanthan gum can even improvethe end result of commericially available conventional floor cleanerswhen diluted using recommended instructions and used in the context ofconventional mopping systems.

1. A process of cleaning a surface, said process comprising the stepsof: applying a detergent composition to said surface, said detergentcomposition having a pH of no more than about 9 and consisting of: a)from about 0.0001% to about 0.2% by weight of xanthan gum, b) from about0.05% to about 0.4% by weight of a linear, non-aromatic detergentsurfactant, c) from about 0.1% to about 5% by weight of a solvent, d) analkaline material consisting of 2-amino-2-methyl-1-propanol to providethe pH of no more than about 9, e) from about 0.0005% to about 0.02% byweight of a silicone suds suppressor, and f) the balance being deionizedwater, and wiping said surface with an absorbent pad having a capacityfor water of least about 15 g/g when measured under a confining pressureof 0.3 psi, such that said detergent composition is absorbed by saidabsorbent pad.